Recent trends in solid-propelled rocket motor designs for tactical weapons have been towards higher operating motor pressure, greater motor length-to-diameter ratios, higher volumetric loadings of the propellant, and longer duration burning times due to employment of lower burning rate propellants. All of these trends result in worsened erosive burning conditions. Erosive burning, thus, strongly effects the efficiency with which the propellant is utilized.
Erosive burning is the term used to describe the condition in which the burning rate of a solid propellant is affected by the flow of high velocity gases parallel to the burning surface. In a typical grain design with flow channels of constant port area, erosion will generally occur inside the central perforation near the nozzle end where the gas velocity is high. Erosion is characterized by an increase in burning rate, and is usually expressed in terms of an erosion coefficient, E = r/r.sub.o, where r is the burning rate with erosion and r.sub.o is the burning rate of the same propellant without gas flow parallel to its surface.
Advantageous would be a means to control erosivity since it would be possible to decrease the channel cross-section and the channel volume and increase the relative amount of propellant in the motor. The erosion is most pronounced at the beginning of propellant burning and diminishes as the flow channel enlarges.
Therefore, an object of this invention is to provide an additive for a propellant composition for controlling the erosivity of the propellant when the propellant is burned in a rocket motor having a large length-to-diameter ratio.
Another object of this invention is to provide a selected additive for a slow-burning propellant composition for controlling the erosivity of the propellant when the propellant is burned in a rocket motor.